Genome-wide analysis of gene family identified key gene for the biosynthesis of bioactive flavonol glycosides in Maxim.

Maxim. is a well-known traditional Chinese medicinal herb with flavonol glycosides as the major pharmaceutically active compounds. UDP-glycosyltransferases (UGTs) are a group of enzymes responsible for the glycosylation of flavonoid glycosides. In this study, a genome-wide analysis was performed to identify family genes in . As a result, a total of 339 putative genes were identified, which represents the largest gene family known thus far, implying a significant expansion of the gene family in . . All were unevenly distributed across six chromosomes, and they were classified into 17 major groups. The expression profiles showed that genes were differentially expressed in roots, leaves, flowers, shoots and fruits. In particular, several were highly induced by high light intensity, which was consistent with the accumulation level of bioactive flavonoids in . . Six genes that were preferentially expressed in roots or leaves were successfully expressed in , and only the recombinant EpGT60 protein was found to be active toward 8-prenylkaempferol and icaritin to produce the key bioactive compounds baohuoside II and baohuoside I. The optimal temperature, pH, and were determined for the recombinant EpGT60 protein. In addition, expression of recombinant EpGT60 in cell culture led to successful production of baohuoside II when fed 8-prenylkaempferol. Our study provides a foundation for further functional characterization of genes in and provides key candidate genes for bioengineering bioactive flavonoids in